A193784 - OEIS

%I #5 Dec 18 2015 18:17:43

%S 6,75,1383,82057,17485499,12269256241,26618983431241,

%T 174570423155403607,3439388112891290777185,

%U 203331913765001724843185283,36063230821901471856813524283909,19188799396869069058685453832499056759

%N Number of n X n symmetric 0..5 arrays with no element equal to the sum or difference mod 6 of any two of its horizontal and vertical neighbors

%e Some solutions for 4X4

%e ..1..5..1..1....1..3..3..4....1..1..5..1....1..3..3..5....1..1..3..3

%e ..5..3..3..3....3..3..3..3....1..3..1..5....3..3..5..5....1..1..1..5

%e ..1..3..1..1....3..3..2..2....5..1..3..1....3..5..3..1....3..1..1..1

%e ..1..3..1..5....4..3..2..2....1..5..1..5....5..5..1..3....3..5..1..3

%K nonn

%O 1,1

%A _R. H. Hardin_ Aug 05 2011